In 1937, the Imperial Japanese Navy issued specifications for a replacement for the A5M Claude to Mitsubishi and Nakajima. The requirements were for a speed of 500 km/h at 4000 m and a climb to 3000 m in 3.5 min. An endurance of two hours at normal power was needed, or six to eight hours at economical cruising speed (both with drop tanks). Armament was to consist of two 20mm cannons and two 7.7mm machine guns and the capacity to mount two 30kg or 60kg bombs. The airplanes would carry all necessary radio equipment and a radio direction finder. In order for it to fit on aircraft carriers, the wingspan had to be less than 12m.